Bugs and worms steal spotlight in wetland restoration

Regulators are shifting from chemistry to biology as they manage stream health

Workers removed tress from the San Marcos Creek floodplain last week as part of a major development project that includes efforts to revive the waterway's ecological function so that it supports more bottom-dwelling creatures such as worms and bugs.
— John Gastaldo

Workers removed tress from the San Marcos Creek floodplain last week as part of a major development project that includes efforts to revive the waterway's ecological function so that it supports more bottom-dwelling creatures such as worms and bugs.
— John Gastaldo

As waterways go, San Marcos Creek is hardly iconic. Even in the spring, it’s barely noticeable next to the city’s hardware stores, banks and eateries.

But the stream has quietly gained regional significance as a test case for an emerging approach to regulating water quality that has broad implications for businesses, residents and aquatic species across California.

Instead of just minimizing the amount of various contaminants in the creek, regional pollution police will regulate how insects, worms and snails fare as San Marcos develops the “creek district.” A permit issued in January by the San Diego Regional Water Quality Control Board was the first of its kind in the region to include biological performance of a waterway as an enforceable standard.

Ecosystem assessments have been used as indicators of riparian health for years. “What we have lacked until now is any requirement for how a stream section functions in terms of biological integrity,” said David Gibson, executive officer of the regional board, which regulates pollution.

The change is part of a decades-long progression of interpreting and implementing the 1972 Clean Water Act. For San Marcos Creek, it means a requirement to boost populations of benthic, or bottom-dwelling, organisms so they score “fair” or “good” on an index that today says they are in poor shape.

Benthic macroinvertebrates

Aquatic invertebrates inhabit the bottom parts of waterways. They are also called benthic macroinvertebrates, and they make good indicators of watershed health because they:

•Live in the water for all or most of their life

•Stay in areas suitable for their survival

•Are easy to collect

•Differ in their tolerance to amount and types of pollution

•Are easy to identify in a laboratory

•Often live for more than a year

•Have limited mobility

Source: U.S. Environmental Protection Agency

The regional board’s parent agency in Sacramento — with support from the U.S. Environmental Protection Agency — is developing rules that should prompt the statewide expansion of a similar approach starting in 2014. Biological mandates likely will work their way into other stormwater permits needed by cities, approvals for working in waterways and mandates to restore polluted areas.

“As a layman, I am convinced this is the simplest long-term measure of how healthy a stream is,” said Gary Strawn, a member of the regional board’s governing panel. “It’s the up-and-coming thing, not just in Sacramento, but nationwide.”

Well before he joined the board, Strawn helped organize the San Diego Stream Team, a group of volunteers who periodically don waders and use specially designed nets to sample creek bottoms for crayfish, worms, flies and other “benthics.” More regulatory emphasis on that kind of data could give residents a greater role in drawing attention to areas where creatures suffer in the roughly 100,000 miles of perennial streams that crisscross California.

Despite decades of work, recent assessments have found that only about half of all stream segments were in good biological condition. A limited review in the San Diego region showed three-quarters of streams were in poor or very poor condition, prompting the regional board to rethink its approach to controlling stormwater contamination.